A. Horizontal and Vertical Control Sufficient horizontal and vertical control points to support this project must be established by the Vendor. All control must be included in the final deliverable to the COUNTY. The Vendor will determine the number, distribution, and collection method (GPS, total stations, etc.) of ground control points required to meet the accuracy specifications. B. Digital Ortho Rectified Photography a. All additions and corrections by Vendor to an existing DEM required to accomplish the rectification to the specified accuracy will be merged by the Vendor into the existing DEM and delivered to the COUNTY as an updated DEM. b. Digital orthos shall be delivered in Arkansas State Plane North, North American Datum 1983, United States Feet c. All data will be delivered in a Vendor derived grid system or a USGS Quad system. In this proposal we will make reference to USGS quads only to describe a grid or tile system. d. At a minimum, digital orthos shall be delivered in the following formats. In no instance should any file size be greater than 1 GB: i. Geo-tiff (projection information embedded in the tiff image header) a tfw for each image shall be supplied as well in quarter-quarter quadrangle format. ii. Mr. SID (compressed 20:1) and “world file” (sdw) for each image shall be supplied for the captured resolution of imagery. These files shall mosaic together with no seam lines and no black or no data areas without regard to layer schema or order placement of tile layers. iii. Mr. SID mosaic of the county (an sdw for each image shall be supplied as well) compressed approximately 50:1. This file shall contain no seam lines and no black or no data areas along borders. e. Digital orthos shall be mosaicked to derive a single seamless orthophoto for each USGS quadrangle format requested. It is recommended that a 100 foot border be included around each SID image. Horizontal displacement of features at mosaicking will be just cause for rejection of the orthophoto. Individual tiles must also be seamless without regard to tiling schema or layer schema or order placement of tile layers. f. Digital orthos shall have a contrast tonal balance of the completed mosaic to remove contrast differences across mosaic lines. g. Digital orthos shall have a contrast adjustment across all contiguous tiles such that the overall project appears similar in tone. C. Digital Oblique Photography a. Oblique imagery shall cover the full extent of the COUNTY as defined in the project scope.
